This invention relates to a carrier apparatus applied to a coating and developing apparatus, for example, for coating a wafer with a resist and developing it, and a processing apparatus provided with the carrier apparatus.
In a photo-resist process of a semiconductor device fabrication, a resist solution is coated on a surface of a substrate such as a semiconductor wafer (referred to as "a wafer" hereinafter) to form a resist film. After the predetermined pattern is exposed on the resist film, the substrate is coated with a developing solution and developed. A coating and developing apparatus is used so far in a series of the processes.
The coating and developing apparatus is provided with processing units which individually perform a series of processes necessary for coating and developing, that is, an adhesion unit, a coating unit, a thermal processing unit, a developing unit and the like. An adhesion unit performs adhesion treatment to improve resist fixing. A coating unit coats a substrate with resist solution. A thermal processing unit heats a substrate coated with resist solution to cure the resist film. Another thermal processing unit heats a exposed substrate at the predetermined temperature. The developing unit develops a exposed substrate.
A carrier apparatus is used for carrying a wafer between each processing unit or carrying a wafer in/out from each processing unit, the carrier apparatus, for example, being able to carry a wafer while holding it.
Recently, a coating and developing apparatus provided with the processing units which are vertically multi-tiered is proposed in order to save an installation space. A carrier apparatus used in this type of coating and developing apparatus needs rapid vertical movement and easy stop control. Needless to say, it is required to minimize the occurrence of dust and take it into consideration not to adhere occurring particles to a wafer.
Thus, a conventional carrier apparatus has the structure described hereinafter. That is, an idler pulley and a driving pulley are disposed vertically. A timing belt is provided between the idler pulley and the driving pulley. A holding portion for holding a wafer is attached to the timing belt through a proper attaching member. A motor with a strong possibility of occurrence of dust is disposed below. A speed reducing belt is provided between an output shaft of the motor and a speed reducing pulley with larger diameter which is disposed on the same shaft as the driving pulley. From the above structure, the timing belt moves vertically by normal rotation and reverse rotation of the output shaft of the motor, whereby the holding portion moves vertically.